Anomalous response of supported few-layer hexagonal boron nitride to DC electric fields: a confined water effect?

We use electric force microscopy (EFM) to study the response of supported few-layer hexagonal boron nitride (h-BN) to an electric field applied by the EFM tip. Our results show an anomalous behavior in the dielectric response of h-BN atop Si oxide for different bias polarities: for a positive bias a...

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Bibliographic Details
Published in:Nanotechnology 2012-05, Vol.23 (17), p.175703-1-6
Main Authors: Oliveira, C K, Matos, M J S, Mazzoni, M S C, Chacham, H, Neves, B R A
Format: Article
Language:English
Subjects:
Bias
Boron nitride
Dielectric constant
Electric fields
Mathematical analysis
Oxides
Polarity
Silicon substrates
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Summary:We use electric force microscopy (EFM) to study the response of supported few-layer hexagonal boron nitride (h-BN) to an electric field applied by the EFM tip. Our results show an anomalous behavior in the dielectric response of h-BN atop Si oxide for different bias polarities: for a positive bias applied to the tip, h-BN layers respond with a larger dielectric constant than the dielectric constant of the substrate, while for a negative bias, the h-BN dielectric constant appears to be smaller. Based on ab initio calculations, we propose that this behavior is due to a water layer confined between the Si oxide substrate and h-BN layers. This hypothesis was experimentally confirmed by sample annealing and also by a comparative analysis with h-BN on a non-polar substrate.
ISSN:0957-4484
1361-6528
DOI:10.1088/0957-4484/23/17/175703